How do I install Libre to an external hard drive?

It only gives me the option to install features to my E drive.
My E drive has all my space, my C drive is completely full.
Examples:

You should really move files from C: to E:
Any OS needs space for temporary files and becomes unstable if there is no such space.

The space required by LO in drive C: is mostly temporary files and shared libraries. Unless you free up some space in drive C: it’s really not a good option to install LO at this point.

Alternatively you can install a Portable version. In a few days version 4.2.4 should be available from WinPenPack or from PortableApps or you can download now 4.1.6 or 4.2.3

Well I’ve tried clearing it up but a lot of programs (like libre) require me to use the C: drive and it only has 50gbs while my E: has 500gbs.